According to the miasma theory of disease, many illnesses are caused by foul odors. These can be avoided by sniffing medicinal vapors, such as vinegar:

Vapours from a vinegar-soaked sponge in the bottom were inhaled through the small holes in the top of the ‘acorn’. If a person felt faint they could also sniff their vinaigrette and the sharp vinegar smell might shock their body into action. The other side of the vinaigrette shows a face and could act as a memento mori – a reminder of death. The skull was probably hung from a piece of cord or necklace and carried at all times.